Fatty acid treatment



D86. 1940- R. H. POTTS ETAL ,224,986

FAT TY ACID TREATMENT Filed March 5, 1938 \T0 saw/15721:: CONDENSER b00450 Ll U/D FA rrnc/os COOLER FOR Llula FnTTr nc/ps TUBE HEATER 1 0/1. D/PHW OFF Dee. 3.7 19

FATTY .ACID TREATMENT Ralph H. Potts, La Grange, and John E. McKee, Western Springs, Ill. assiznors to Armour and Company, Chicago, 111., a corporation of Illinois Application March 5, 193a, Serial No. 194.050

4 Claims. (01. 202-46) This invention relates to an improved process and apparatus for the treatment of vegetable, animal and marine oils containing fatty acids, and has particular reference to the separation of 5 volatile constituents from such materials, includ- I ing the removal ofodor-imparting substances therefrom.

As described in our copending application Serial No. 98,732, filed August 19, 1936, of which 10 the present application is a continuation in part.

it has been found highly advantageous to subject 7 fatty acid mixtures'of a process for separating the mixtures into volatile fractions having different boiling points. This procedure involves 1g heatingthe oleaginous materials, distilling the volatile portions thereof in a bubble tower, con- (lensing the vapors and returning the condensed vapors to the upper portion of the tower in cooled, liquid condition. 7

20 The present invention has as its principal object an improvement in processes of this general typein whichthe fatty acid mixtures are subjected to distillation and the cooled distillate is returned to the process, the invention includ- 2& ing an improved deodorization process for use in fractionating systems as well as in the straight run distillation of fatty acids from oleaginous materials.

An additional object of the invention is the so provision of a process and apparatus for the distillation of fatty acids in which previously condensed fatty acids are subjected to a separate cooling operation and then are employed for the condensation of fatty acid vapors and removal of as odor-imparting constituents.

Still another object of the invention is to'provide a method and apparatus for the continuous refining and deodorization of fatty acid-containins vegetable, marine and animal oleaglnous so materials.

A further object of the invention is the provision of an improved process and apparatus for the purification of triglycerides containing relatively small quantities of fatty acids and odor as imparting volatile substances.

These and other objects of the invention will be evident upon a consideration of the following description of a preferred embodiment of the invention and by reference to the accompanying 50 drawing, in which Fig. l is a somewhat diagrammatic view insection showing apparatus for the continuous treatment of oleaginous materials in accordance with the invention; and

as Fig. 2 is a view of apparatus particularly.

adapted for the batch refining and deodorization of vegetable oils.

- taining a relatively small quantity of free fatty acids of the volatile type and odor-imparting constituents. The treatment includes removal of the fatty acids and the odor-imparting constituents to leave a relatively pure, edible oil. The 0 invention likewise is applicable to the removal of odors during the separationv of fatty acids into volatile constituents, as described in our copendlng application and in our prior patent.

Raw vegetable oils generally contain a small 15 percentage of free fatty acids which are objectionable where the oil is to be used for edible purposes. Also; the oil usually has some odorimparting constituents of a relatively low boiling nature. go

In the apparatus shown in Fig. 1 the column I! contains a series of vertically spaced bubble plates it having down spouts l2 and bubble caps ii of conventional construction! A column of this sort can be used for the straight distillation as of fatty acids-or it can be used in the fractions-- tion of the fatty acids into products of diflerent volatility, as described in our prior .patent. For the latter use the tower or column preferably is considerably higher than where the apparatus is so to be used for straight distillation purposes. The oleaginous material which it is desired to treat is subjected to a continuous heating operation in the pipe still or tube heater indicated generally at ll. This tube heater may be of the as type disclosed in our previous patent in which the material to be heated is passed at a rapid rate of travel through an enclosed zone or pipe subjected to a heated gas. The oil is heated to a temperature which is sufdciently high to vaporize o the volatile constituents thereof at reduced pres sure. In passing the oil through the tube heater i Ht is preferable to include steam along with the oil. For ordinary deodorization and removal of free fattyacids from the oils to be refined, it gs generally is sufficient if the oil is heated to a temperature of about 425 F. to 475 F. in the tube still ll, although higher or lower temperatures may be employed, depending upon the nature of the volatile impurities and other operating factors 50 of the process such as the absolute pressure maintained in the system. v

The heated oil and fatty acid mixture is introduced into the column in through a valvecontrolled line l5. It will be noted that line l5 as i qnuntity c ceeeee I maintained at the" desired oomtantpoint' by" different volatility. The refrigerating apparatus 22 is mode of such sized capacity as to make it to return at reletively large unntity of the condensed fatty acids to the upper plates to act as reflux in this manner.

The heat necessary for the fractionation may be supplied at least in port by recycling the unspiit triglycerides obtained from the bottom of the tower and by the superheated steam used in the process. The heating operation in the case irectionstion generally will lnvolve'rnising the I temperature of the oleaginous material to a higher point than in the case of the deodorisation end refining of an oil containing a relatively small iotty colds. Hydrolyned triglycerides treated as by the l ritchell process may contain as much as 95pm cent or more of free fatty acids.

To iractionate such fatty acids the heating operwhich may mice the temperature of the material to the order of 550% F. steam at a temperature of about 500 1''. may be passed through the heatin tube with the fatty acid materials.

The heated mixture is fleshed into the column and the fatty acid vapors pass upwardly through the bubble trays providing zones of previously condensed fatty acids of progressively decreasing vaporization temperatures. The qusntity'of liquid istty colds returned to the column preferably is considerably greater than the quantity of such iatty acids removed from the process. The particulnr conditions of the'fatty scid return will depend upon such factors as the number of fractions which the fatty acids are being divided into and the thoroughness of the separation desired.

Higher boiling liquid fractions may be removed from any of the intermediate plates of the tower.

end undistilled residue may be withdrawn from the bottom of the tower.

'Ihe absolute pressure at the top of the column may be between and mm. Hg, while at the vnpor inlet it in desired to hold the pressure to between 30 and mm. Hg. The withdrawal. of liquid fatty acids from the upper plates of the column end refrigeration of these liquid low boiling fractions before returning the same to the tower in effect provides an internal condenser for the column. That is, the lowerboiling fatty acids rising to the top of the column are condanced directly in the column to provide reflux liquid end to provide the means for condensing further quantities of the fatty acids.

lite embodiment of the apparatus shown in Fig. 2 is particularly desirable for the refining and deodorisation of batches of an oil such as palmoil, which, usually will not contain a very greet quantity of free'fatty acids. Any desirable type of heating equipment may be employed to host the oleaginmls material to the extent necessary for vaporization oi. the free fatty acids and odordmparting constituents. The heated matericl is subjected to o. vaporization step for volatilizetion of the fstty acids and odor-imparting constituents with steam, the resulting vaporous mixture paming into the treating tank ll through the inlet opening Q i A heme 82 directs the vapors downwardly. Tank so is. maintained under sub: stsntially reduced pressure by means of the line 458 leading to e. suitable vacuum creating device.

in the bottom of the tank 0 are positioned a series of cooling coils 44 through which is passed 2. refrigerant such as water. Positioned above these coils and the inlet H is a bubble plate ll having bubble cape M and a down spout 4'! extending from the bubble cap to the lower portion of the tank. The liquid level in the tank I. is

branch line leading to thebubble plate 40, as

- the process the vaporous material, including the sponding temperature.

is such that a maximum temperature of about.

municating with the bottomofthe tankis aline s i2, and this line leads from the tank through the pump 58 to the line 5!. The discharge pump [8 also communicates with a branch line i, this shown in the drawing. 7

In operation of the device shown in Fig. 2. the vaporous mixture may enter the inlet ii at e temperature of the order of 350 1'. at 5-25 mm.

Hg absolute pressure. Under the conditions of free fatty acids, odor-imparting constituents and steam, pass upwardly through the bubble plate ll. There is circulated'across the bubble plate ll chilled liquid fatty acids from the bottom of the tank.- T'he pump "maintains a circulation of chilled liquid fatty acids thro h the line I4. across the bubble plate 40, down the downspout 41 and through the outlctopening II. The rate of circulation of these liquid fatty acids and the degree to which their temperature is reduced are factors which provide for reduction of the 'temperature of the vaporous fatty acids passing upwardly through the bubble plate 4! sufficiently to condense these fatty acids. The'condensed fatty acids then Join the circulating stream. As

the liquid fatty acids accumulate. they are withdrawn through the line ll to an extent determined by the liquid level control device 40.

The refrigeration coils cool *the liquid fatty acids in the bottom of the tank to a temperature of the order of to F. and the liquidfatty acids are poured onto the bubble tray at a oo'rre The rate of circulation 200 F. is reached as the liquid fatty acids pass from the line I across the bubble plate to the downspout 41. As the vaporous fatty acids enter the tank in admixture with superheated steam, the steam passes-upwardly through the bubble tray and out the line 43. To prevent incorporation of mist in this steam it is preferable to proa vide a Venetian blind type of mist extractor N in the upper portion of tank 40.

A mixture of fatty acid vapors and steam presents a particular problem from the standpoint of liqusfying the fatty acids. The particle size of the fatty acids'when the vapor temperature is reduced below the condensation point of the fatty acids is so small that the liquid particles tend to be carried along with the vapor stream. thereby making separation into liquid fractions extremely difficult.

In an example of refining palm oil approximateiy v000 poundsbf steam is blown into the charge of palm oil per hour and 8 hours may be 60 necessary for completing the refinement of the oil by elimination of fatty acids and odoriferous materials. The emu temperature of the charge may be of the order'of 430" I"..- and the quantity of the oil of the order of moo pounds. As this oil contains approximately? percent-of free fatty acids, it is required that 1050 pounds of fatty, acids must be removed. By far the greatest portion of this acid isremoved during the first two hours. The mixture (of fatty acids and steam may enter the vapor separatorat about 350 F. and a pressure of 5-36 mm. of mercury The refrigeration of the liquefied fatty acids and circulation in the separator is controlled to reduce tho temperature from 350 F. to approximately-.200 "to F. on the bubble tray. This necessitates removal of 1 condensation of the fatty acids tosibie in condensed liquid iatty acids and the steam. The quantity of fatty acids removed per hour determines the circula- "ui is of the cooled fatty acids. In the above ie where the fatty acids are removed at the rate of soc pounds of acid per hour, it will be necessary to circulate about 6600 pounds per hour of so i d fatty acids having an inlet temperature and an outlet temperature at Lil of 208 4 In each of the types of apparatus shown in the d it .i be noted that there is provided a 5 its ldE condensation of vaporous fatty acids from a mixture of fatty acids and steam. the process involving reduction of the temperature oi vapor-cue fatty acids to below their condensation temperature by contact thereof with previously condensed and chilled fatty acids of similar nature. As has been described, this process may be utilized in the straight run distillation of fatty acids, in the refining of residual fatty acids snd cdoriierous imparting substances as impurities in oil, and in general is applicable to the condensation fatty acids from a mixture thereof with The process has many advantages over other types of heat exchange condensation processes. It will be recognized that the process and apparatus may be varied somewhat from the explanative description given without departing from the scope of the invention as defined in the appended claims. As an example of permissible changes, more than one bubble tray may be employed in the apparatus of Fig. 2.

..i.i be observed that in each or the modifications shown in Figs. i and 2 the acids of the upper zone are cooled by being passed info indirect heat exchange on with e. coolingfluid. By the term "indirect heat exchange relation" we mean the acids are in contact with a conduit carrying the cooling fluid. like is shown in Figs. 1 and 2, or are otherwise in heat transfer relation while avoiding direct admixture with the cooling fluid. The odoriferous materials are volatile, usually more volatile than the fatty acids and are therefore carried out by the steam, although a portion may condense with the condensed fatty acids on the upper plate across winch refrigerated liquid fatty acids are circulated. The steam passing through the circulating fatty acids has a stripping effect upon the volatile odoriferous materials, thereby preventing undue accumulation of odorimparting impurities in the fatty acids and perbod " mitting the recovery of arelatively pure and odor- Thus, in the refining steam, leaving a thoroughly deodorized oil and a liquid fatty acid product.

We claim:

1. A process of treating oleaginous materials containing free fatty acids comprising vaporizing volatile constituents of said materials in the presence of steam to thereby "form a vaporous mixture including fatty acids and steam, passing said vaporous mixture into is zone containing previaszsese ously condensed fatty acids where said vaporous mixture comes into contact with said condensed fatty acids, passing liquid fatty acids from said zone into indirect heat exchange relation to a cooling fluid to maintain the liquid fatty acids in said zone at a temperature below the condensation temperature of said vsporcus fatty acids and above the condensation temperature of said steam whereby to condense said vaporous fatty acids in said zone and to pass said steam from said zone in vaporous form, and recovering liquid fatty acids from said zone.

2. A process of treating oleaginous materials containing fatty acids and low boiling odor-imparting substances, comprising vaporizing volatile constituents of said materials in the presence of steam to thereby form a vaporous mixture including free fatty acids, odor-imparting constituents, and steam; passing said vaporous mixture into a zone containing previously condensed fatty acids where said vsporous mixture comes into contact with said condensed fatty acids; circulating liquid fatty acids from said zone into indirect heat exchange relation to a cooling fluid to maintain the liquid fatty acids in said zone at a temperature below the condensation temperature oi? said vaporous fatty acids and above the condensation temperature of said steam and odorimparting substances whereby to condense said vaporous fatty acids and to pass said steam and substantial amounts of said substances form said zone in vaporous form, and recovering liquid fatty acids from said zone.

3. A process of deodorizing glycerides containing free fatty acids and low boiling odor-imparting substances; which comprises vaporizing in the presence of steam fatty acids and odor-imparting substances contained in said glycerides, separating the vaporous mixture thus produced from said glycerides, passing said vaporous mixture into a zone containing previously condensed fatty acids of similar nature, where said vaporous mixture comes into contact with said condensed fatty acids; circulating the liquid materials in said zone into indirect heat exchange relation to a. cooling fluid to maintain the temperature of said liquid materials in said zone below the condensation temperature of the vaporous fatty acids and above the condensation temperature of said steam, whereby to condense said vaporous fatty acids in said zone and to. pass said steam from said zone in vaporous form.

4. A process of treating oleaginous materials containing fatty acids, comprising passing said materials downwardly through a lower series of zones against a countercurrent of steam whereby fatty acids are carried upwardly in vaporous form in admixture with said steam, passing said vaporous mixture through an upper zone containing similar previously condensed fatty acids, where said vaporous mixture .comes into contact with said condensed fatty acids, circulating liquid fatty acids from said upper zone into indirect heat exchange relation to a cooling fluid to maintain the liquid fatty acids in said zone at a temperature below the condensation temperature of said vaporous fatty acids and above the condensation temperature of said steam whereby to con dense said vaporous fatty acids without condensing said steam, and recovering condensed fatty acids from said upper zone.

RALPH H. PO'I'IS. JQHN E. McKEE. 

